File drawer units and the like, as used in offices and similar environments, are conventionally provided with a locking mechanism so as to securely lock the drawers in a closed position. Such mechanisms conventionally employ a key-operated lock device which is mounted so as to be accessible from the front side of the housing, which lock device acts through a suitable intermediate linkage for controlling a vertical lock bar which is disposed adjacent one of the corners of the housing. This lock bar in turn is provided with locking elements which cooperate with the individual drawers to securely lock them in their closed position. While numerous locking mechanisms of the above-described type have been devised and utilized, most such mechanisms employ a lock bar which is suitable only for one drawer configuration, or for use with a plurality of identically sized drawers, and hence do not permit a plurality of different-sized drawers to be readily positionally rearranged, or replaced with more or less drawers of different size. This has generally required the manufacturer to provide different lock mechanisms for different drawer units, and has prevented changing of the drawer arrangements after the units are installed in the field.
In an attempt to improve upon this disadvantage, one drawer unit is known which possesses a vertically elongated lock bar having multiple positions thereon for receiving removable locking tabs. The removable locking tabs can be selectively mounted on the lock bar at those positions corresponding to the location of the drawers and, when the different sizes of drawers are positionally rearranged, then the locking tabs can be positionally rearranged to correspond to the new drawer arrangement. While this obviously does increase the flexibility and adaptability of the unit both during manufacture and use, nevertheless this unit still requires that the correct number of locking tabs be initially selected, and then properly positioned and mounted on the lock bar at the correct locations, or in the alternative the removal and remounting of the lock tabs at the desired locations. A lock mechanism of this general type is illustrated by U.S. Pat. No. 3,857,620.
Another requirement of lock mechanisms of this general type is the necessity that the mechanism permit an opened drawer to be returned to its closed position, even when the lock mechanism is already in its locked position. While the mechanism of the aforesaid patent does permit closing of a drawer when the lock mechanism is in its locked position, nevertheless this drawer closing function requires that the locking tab be provided with a complex three-dimensional configuration to cam the entire lock bar vertically upwardly so as to permit the opened drawer to be moved therepast during its closing movement. The mechanism of this patent employs a positive linkage between the lock device and the lock bar, and hence requires lifting of the lock bar to permit the closing of a drawer when the mechanism is locked.
Accordingly, it is an object of this invention to provide an improved lock mechanism for controlling a plurality of drawers or similar slidable units, which lock mechanism possesses the essential performance features but in addition overcomes the above-mentioned disadvantages. More specifically, the lock mechanism of this invention employs a vertically elongated lock bar having a plurality of vertically spaced locking tabs mounted thereon at selected intervals, which lock tabs are permanently fixed to and remain on the bar at all times. The drawer unit employs a cabinet which mounts therein a plurality of drawers, which plurality can vary in number and/or size so as to permit the user to select the optimum drawer arrangement. Irrespective of the number and/or sizes of drawers selected, however, and/or the positional arrangement thereof, the same lock bar still cooperates with and lockingly holds all of the drawers in a closed locked position when activated, without requiring any prepositioning or rearrangement of the lock bar. In addition, when the lock mechanism is activated into a locked position, an open drawer can still be readily moved into its closed position without undue effort since the lock bar will readily displace against the urging of a spring so as to permit the lock stop on the activated drawer to move therepast, following which the lock bar again automatically returns to its closed and hence locking position.
Other objects and purposes of the invention will be apparent to persons familiar with mechanisms of this general type upon reading the following specification and inspecting the accompanying drawings.